There are certain common packaging materials that seem innocuous to most folks, but cause consternation in the field of conservation. Many “non-archival” materials are so ubiquitous that they frequently turn up in archives and museum storage areas. One such material is Bubble Wrap®.
Although it is squishy, entertaining to pop, and may be viewed as an emblem of modern progress, Bubble Wrap® can be harmful to the collections it is meant to protect. This is probably a shock to most readers. It certainly does a great job of preventing breakage and it does have its place, but it has an annoying habit of imprinting its lovely dot pattern on museum treasures.
The problem is in the plastic. Plastics for most everyday uses are generally designed to be disposable, and are not stable materials with longevity. They contain a wide range of fillers, plasticizers, and undisclosed compounds made to facilitate the manufacture process and create the desired physical properties. Plasticizers in flexible plastics, such as Bubble Wrap® film, are not exactly attached to the polymer. What they do is act as a fluid to allow the polymer molecules to move around, creating flexibility. Since the plasticizers are not fixed, they tend to exude from the plastic. The plasticizers can act as a solvent for other plastics, paints and inks. Have you ever had a vinyl 3-ring binder that, over time, acquired an imprint from one of the printed pages inside? This is one example of the plasticizer from the polyvinylchloride polymer moving out of the plastic and partially dissolving the printing inks.
But back to Bubble Wrap®. Typically the side of the material that causes a problem is the bubble side. Damage from Bubble Wrap® has been noted on varnishes on woods, metals, gilded frames, and polished surfaces. It causes corrosion to metal, etches surfaces, and can solubilize paints. I personally have observed damage to an acrylic book cradle, which had an etched pattern of circles on the surface, and a Native American pot with a highly polished finish. In both cases the packing material was used for shipping purposes and neither one had been stored in the Bubble Wrap® for an extended period. In cases were a surface paint or varnish has been affected, this damage may be irreversible, or extremely time consuming for a conservator to correct.
If you are packing fragile or valuable items that you care about, there is a safe way to use Bubble Wrap®. Enclose or fully wrap the article in acid free tissue (for long-term storage), or unprinted newsprint and then follow with the Bubble Wrap®. Also take care that any tapes used to secure the packaging materials do not contact your item. Using this method your items will be safe from damage!
Laura Wahl is the library conservator at Hagley Museum and Library.